Microsoft calls for 16-core server SoCs

SAN JOSE, Calif. – A Microsoft executive called for a new class of multicore system-on-chips to drive the lower power servers needed for tomorrow's data centers. But he poured cold water on ARM-based chip vendors, hoping to get design wins in such systems.

"I've been involved in instruction-set architecture transitions multiple times, and they are extremely painful," said Dileep Bhandarkar, a distinguished engineer in Microsoft's data center group, speaking at the Linley Data Center Conference here.

"The rule of thumb is to make that kind of change you have to have at least a sustainable 2x performance improvement per dollar or per watt—and ARM is not there," he said.

"ARM's interesting to look at, and if it lights a fire under Intel and AMD that makes us happy," said Bhandarkar, an Intel CPU and server design for several years before joining Microsoft four years ago.

The breadth of server software used in today's data centers makes use of ARM unlikely in the foreseeable future, even through Microsoft announced it will support ARM in the next version of Windows, he added.

Instead, Bhandarkar called for 16-core SoCs based on Intel Atom or AMD Bobcat cores. Such chips should integrate all the core logic and I/O functions the companies now put in separate chips, he said. "There's a huge opportunity using these smaller cores to be more energy efficient, and we are talking to both AMD and Intel [about that]," he added.

Microsoft operates between ten and 60 data centers worldwide, each using thousands of servers to run its online business that has hundreds of millions of email, Web and search users.

So far the centers use only x86 chips, typically the lowest power versions. It is currently using dual-socket boards with quad-core chips using a single virtual machine per core.

Bhandarkar described a streamlined x86 server design Microsoft will use for its upcoming fourth-generation data centers, inviting others to adopt the system. Microsoft has not published a specification for the servers, but Bhandarkar said he will reveal more details of the design in a blog in the next few weeks.

The new Microsoft design defines a single node as two low power x86 CPUs in a half-size board that includes one PCI Express slot, 4 DIMM sockets per CPU populated with low-power DRAM and four Serial ATA connectors linked to four hard disk drives. Two of the servers and eight drives total are placed in a 1U rack-mounted unit so that 96 servers can be crammed into a standard rack.

Microsoft currently uses a dual-ported 1Gbit Ethernet link for clustering, with only one port active. It may be two years before it populates its open PCI Express slot to shift to 10Gbit Ethernet.

Microsoft has shared the details of its spec with as many as four server makers. By contrast, its archrival Google is well known for keeping secret its proprietary design for servers it uses in its data centers.

"We don’t restrict vendors from not selling our design to others," said Bhandarkar. "High volume drives lower prices, so to the extent there's a single standard that's good, as long as it's my standard," he said.

To further simplify its design, it is moving to using outside air for cooling with minimal use of air conditioning and moving the temperature of its data centers toward 85 degrees Fahrenheit. It has also defined a larger unit of integration, a 20-foot, 160 KW data-center-in-a-box larger than the shipping containers it currently uses in facilities in Chicago.

@Robotics Developer: Just to clarify, the Windows division of Msoft will support ARM in its next-gen product. Dileep, who is a thought leader in the division of Msoft that runs big data centers, is more bullish on x86 retaining its dominance in the server-system space than he is on ARM making any big in-roads there anything soon given the huge s/w support issues beyond Windows.

~2/3rds of ARM shipments go into mobile applications. Of, the other 1/3rd, a lot of these units go in the microcontroller area. But there is a pretty respectable amount of "A" profile processors into automotive infotainment, TVs and other home gadgets. Definitely on a path to number 1 in the digital TV space with 3 of the top 4 now shipping ARM Powered platforms. But yes, the point in time where ARM has meaningful market share in applications such as servers and networking infrastructure equipment is years, not months, away.

This perspective is based on my prior experience with embedded applications. If you want a specific answer to your OS question, then you will need to address Microsoft....
The big challenge with the embedded operating system vendors that I have worked with in my last (too many!) years is that the port to a new architecture is a relatively small part of the total cost. The bigger cost is ensuring that software runs with a myriad of applications, supporting the product in the market and then and then continually driven forward (while ensuring that legacy apps will still keep working with the new revision etc).

Rick
Thanks for the shout out!
A quick clarification - Marvell has an architecture licence. So the processor core in the Armada-XP device is not the Cortex-A9. It is their own processor. But utilizes the same version of the ARM instruction set as the Cortex-A9
Ian

So if I understand the current approach: Microsoft wants to pick up on the ARM based designs with Windows BUT is not interested in ARM based servers. Is there significant differences between porting Windows to ARM platforms and using that port for servers? If the work is similar than the effort is already going to be made (I think?). Just wondering what I missed..

OK a couple insights: ARM now has a full time director level exec working on smoothing the path to the data center for the architecture by assuring solid ports and optimized performance of Java enterprise software, Linux OSes and other key libraries. Tilera has some design wins for its 32-bit, 64-core VLIW part in data centers, but said Top Tier data centers require 64- bit support even for the Web server systems, and Marvell said everyone is evaluating its four-core A9 SoC but no one has made any purchase decisions yet.

Microsoft disclosing their server design to the vendors is really interesting. They are making it open to all and want other small businesses to actually follow a standard solution. This will give great visibility to the supplier of critical components in these servers and could actually result in more sales for the suppliers.